Sheet container

ABSTRACT

A container in which a stack of sheet material is stored for the subsequent advancement therefrom. The container includes a base plate having a flexible sheet with a portion of the upper surface thereof adapted to engage the under surface of the advancing sheet. The foregoing abstract is neither intended to define the invention disclosed in the specification, nor is it intended to be limiting as to the scope of the invention in any way.

O United States Patent 11 1 1111 3,847,385

Wifilllch Nov. 12, i974 i 1 SHEET CONTAINER Primarv Exanziner--Jz1n1csB. Marbcrt 75 Inventor. Francis Wreloch P f ld, N.Y. 1 J en 1e Assistan!Examiner-James W. Miller [73] ASS gHEe XEI'OX P fi Stamford, Attorney,Agent, or Firm-H. Fleisher; C. A. Green; J.

Conn, J. Rulabate [22] Filed: Nov. 13, 1972 STR CT 57 AB A [21] Appl.No.: 306,270 1 A contamer in which a stack of shect material is storedfor the subsequent advancement therefrom. Cl 271/203 The containerincludes a base plate having 11 flexible [51] Illt. heet with a portionof the upper surface thereof Field of Search i l adapted to engage theunder urface 0f the advancing 271/121-125, 22, 208; 206/57 R Sheet Theforegoing abstract is neither intended to define [56] References theinvention disclosed in the specification, nor is it UNITED STATESPATENTS intended to be limiting as to the scope of the invention3,237,935 3/1966 Becker et al 271/148 in any way. 7 3,522,878 8/1970Rosenburg 206/57 R 3,640,524 2 1972 Fredrickson 271/121 5 Claims, 3Drawmg Figures PATENTEDHUV 12 I974 3841.385 SHEEI 20$ 2 SHEET CONTAINERBACKGROUND OF THE INVENTION This invention relates generally to. acontainer for supporting a stack of sheet material which is to bedispensed therefrom, and more particularly, to a container adapted tofacilitate seriatim feeding of succes sive uppermost sheets from thestack of sheet material disposed therein.

Typical electrophotographic printing machines utilized in businessoffices are provided with cut sheets of support material. The sheets areused as an imaging receiving member in the printing machine. Althoughpaper is the most commonly used sheet material, certain non-fibrousplastic sheets characterized generally by having a high surface glossand a smooth surface are increasingly employed. These non-fibrous sheetsare frequently more durable than paper and, when transparent, have greatutility as transparencies, i.e., a con ventional projector may projectimages therefrom onto a screen.

Generally, the sheet material is of a preselected size and advancesthrough the printing machine, one sheet at a time, for suitableprocessing therein. Inasmuch as copies may be made at high speeds, it isadvantageous to stack a pile of sheets in the printing machine feedingmechanism which advances automatically one sheet at a time therefrom.The sheets are advanced until the stack thereof is depleted, whereuponthe operator refills the machine with a new stack of sheets. However,when non-fibrous sheet material is substituted for paper operationaldifficulties frequently occur. For example, in feeding successivenon-fibrous sheets, it is found that the top sheet often causes creep oradvancement of the sheetsimmediately therebelow. This results inmisfeeds and jams within the machine, thereby greatly increasing theamount of wasted sheets and the ensuingcost of the operation. Inaddition thereto machine downtime, i.e., the time necessary to clear themachine of sheet jams, is substantially greater than if misfeeds or jamsdid not occur. It appears that jams and misfeeds are caused by therelatively high sliding friction between successive non-fibrous sheetsand, also, by the electrically insulating nature of the nonfibroussheets which permits an accumulation of electrostatic charges thereon.Electrostatically charged sheets attract one another making separationthereof more difficult.

The utilization of non-fibrous sheets as transparencies inelectrophotographic printing machines becomes more significant with theadvent of multi-color machines. In a multi-color electrophotographicprinting machine, it is highly desirable to have the capability ofcreating multicolortransparencies. Transparencies of this type arefrequently required for display purposes, i.e., via projection ontoscreens for seminars or business meetings. Hence, there is continuingneed for more trouble free feeding and processing of nonfibrousmaterial, particularly for multi-color electrophotographic printingmachines.

Moreover, it is desirable to pre-package the stack of transparent sheetsfor shipping to minimize handling maintaining the sheets substantiallyfree from dirt and finger prints. In addition thereto, a prepackagedstack of transparencies is automatically keyed to the proper orientationfor use in the printing machine, i.e., the preferred sheet side has thetoner powder images deposited thereon and coalesced thereto.

Accordingly, it isa primary object of the present invention to improvethe container storing a stack of sheet material therein so thatsuccessive feeding of sheets therefrom isfacilitated.

SUMMARY OF THE INVENTION BRIEF DESCRIPTION OF THE DRAWINGS Other objectsand advantages of the present invention will become apparent uponreading the following detailed description and upon reference to thedrawings, in which: r

FIG. 1 is a schematic view of an electrophotographic printing machineincorporating the present invention therein;

FIG. 2 is a perspective view of a container used in the FIG. 1 printingmachine for storing sheet material therein; and

FIG. 3-is an elevational view of the FIG. 2 container cooperating withthe FIG. 1 printing machine feeding mechanism for the advancement ofsheet material therefrom.

While the present invention will be described in connection with apreferred embodiment thereof, it will be understood that it is notintended to limit the invention to that embodiment. On the contrary, itis intended to cover all alternatives, modifications and equivalents asmay be included within the spirit and scope of the invention as definedby the appended claims.

DETAILED DESCRIPTION OF THE INVENTION For a general understanding of thedisclosed electrophotographic printing machine in which the presentinvention may be incorporated, continued reference is had to thedrawings wherein like reference numerals have been used throughout todesignate like elements. FIG. 1 schematically illustrates the variouscomponents of a printing machine for producing multi-color copies from acolored original. Although the container of the present invention isparticularly well adapted for use in an electrophotographic printingmachine, it should be come evident from the following discussion that itis equally well suited for use in a wide variety of printing machinesand is not necessarily limited in its application to the particularembodiment shown herein.

The printing machine illustrated in FIG. 1 employs a photoconductivemember having a rotatably mounted drum 10 with a photoconductive surface12 thereon. Basically, drum 10 is rotated in the direction of arrow 14to pass sequentially. through a series of processing stations A throughE, inclusive. Drum 10 and other machine operating mechanisms are drivenat a predetermined speed relative to each other from a common drivemotor (not shown). The various machine operations are coordinated toproduce the proper sequence of events at the processing stations.

' Drum initially moves photoconductive surface 12 through chargingstation A. Charging station A has positioned thereat a corona generatingdevice indicated generally at 16. Corona generating device 16 extends ina generally transverse direction across photoconductive surface 12. Inthis manner, corona generator device 16 is adapted to chargephotoconductive surface 12 to a relative high substantially uniformpotential. Preferably, corona generator device 16 is of a type describedin U.S. Pat. No. 2,778,946 issued to Mayo in 1957.

Drum 10 is next rotated to exposure station B where photoconductivesurface 12 is exposed to a color filtered light image of the originaldocument. Exposure station B includes a moving lens system, generallydesignated by the reference numeral 18, and a color filter mechanism,shown generally at 20. A suitable moving lens system is disclosed in U.S. Pat. No. 3,062,108 issued to Mayo in 1962. As shown in FIG. 1, anoriginal document 22, such as a sheet of paper, book or the like,

' is placed face down upon transparent viewing platen 24. Lamp assembly26 and lens system 18 are moved in a timed relation with drum 10 to scansuccessive incremental areas of original document 22 disposed uponplaten 24. Thisproduces a flowing light image of original document 22onphotoconductive surface 12. During exposure, filter mechanisminterposes selected color filters into the optical light path of lens18. The color filter operations on the light rays passing through thelens to record an electrostatic latent image on photoconductive surface-12 corresponding to preselected special region of the electromagneticspectrum, hereinafter referred to as a single colorelectrostatic latentimage.

The single electrostatic latent image recorded on photoconductivesurface 12, is next transported to development station C. Developmentstation C includes thereat three individual developer units, generallyindicated by the reference numerals 28, 30 and 32, respectively. Asuitable development station employing a plurality of developer units isdisclosed in copending application Ser. No. 255,259 filed in 1972.Preferably, the developer units are all of the type generally referredto in the art as magnetic brush developer units. Typical magnetic brushsystems utilize a magnetizable developer mix which includes carriergranules and toner particles. The developer mix is continually broughtthrough a directional flux field to form a brush thereof. Theelectrostatic latent image recorded on photoconductive surface 12is'developed by bringing the brush of developer mix into contacttherewith. Each of the respective developer units contain discretelycolored toner pqrticles corresponding to the complement of the spectralregion of the wavelength of light transmitted through filter 20, e.g., agreen filtered electrostatic latent image is made visible by depositinggreen absorbing magenta toner particles therein, blue and red latentimages are developed with yellow and cyan toner particles, respectively.

Drum 10 is next rotated to transfer station D where the toner powderimage adhering electrostatically to photoconductive surface 12 istransferred to a sheet offinal support material 34. Final supportmaterial 34 may be, amongst others, plain paper. However, the containerof the present invention is particularly adapted for use with anon-fibrous sheet of support material.

A preferred polymeric non-fibrous sheet of support material ispolysulfone thermoplastic available in sheets of approximately 4 milsthickness under the trademark Rowlex from Rowland Products, Inc.,Kensington, Conn. This material, in sheet form, is very transparent andmay be processed satisfactorily to receive thereon a high qualitycoloredimage corresponding to the original document to be reproduced.Another polymeric non-fibrous material for use herein is polyethyleneterephthalate polyester transparent sheet material available under thetrademark Mylar from the E. l. DuPont De Nemours Co., and may beobtained in a wide range of thicknesses. Many transparent, as well asopaque polymeric materials are available in the art which may be formedinto films to receive multicolor images thereon. Any suitable hightemperature coated film formable polymeric material may be used.

Bias transfer roll, shown generally at 36, recirculates support material34 and is electrically biased to a potential of sufficient magnitude andpolarity to attract electrostatically toner particles from the latentimage recorded on photoconductive surface 12 to support material 34. Asuitable electrically biased transfer roll is described in U.S. Pat. No.3,612,677 issued to Langdon in 1971. Transfer roll 36 rotates insynchronism with photoconductive surface 12. Inasmuch as supportmaterial 34 is secured releasably thereon for movement in arecirculating path therewith, successive toner powder images may betransferred thereto in superimposed registration. Support material 34 isadvanced from a stack thereof disposed in a container, indicatedgenerally at 38. Feed roll 40 in operative communication with retardroll 42 (FIG. 3) advances and separates the uppermost sheet from thestack disposed within container 38. Container 38 will be describedhereinafter in detail in association with FIGJ2. The cooperativerelationship between feed roll 40, retard roll 42 and the stack of sheetmaterial disposed within container 38 will be discussed hereinafter, indetail, with reference to FIG. 3. The advancing sheet moves into chute44 which directs the sheet into the'nip of register rolls 46.Thereafter, gripper fingers 48 mounted on transfer roll 36 securereleasably thereon support material 34 for movement in a recirculatingpath. With continued reference to FIG. 1, sheet 34 is stripped fromtransfer roll 36 and advanced with the thermoplastic coated side down,on endless belt conveyor 50 to fixing station E where a fuser, indicatedgenerally at 52, coalesces the transferred powder image to sheet 34. Onetype of a suitable fuser is described in U.S. Pat. No. 3,498,592 issuedto Moser et al. in 1970. After the fixing process, sheet 34 is advancedby endless belt conveyors 54 and 56 to catch tray 58 for subsequentremoval therefrom by an operator.

Although a preponderance of the toner material is transferred to thesupport material, invariably some residual toner particles are leftbehind on photoconductive surface 12 after the transfer of the powderimage to support material 34. This residual toner is removed from thedrum as it moves through cleaning station F. Here the residual toner isfirst brought under the influence -of a cleaning corona generatingdevice (not shown) adapted to neutralize the electrostatic chargeremaining on the material. The neutralized toner is then mechanicallycleaned from photoconductive surface 12 by a rotatably mounted fibrousbrush 58. A suitable brush cleaning device is described in U.S. Pat. No.3,590,412 issued to Gerbasi in 1971. Rotatably mounted brush 58 ispositioned at cleaning station F and maintained in contact withphotoconductive surface 12. In this manner, residual toner particlesremaining on photoconductive surface 12 after each transfer operationare removed therefrom.

It is believed that the foregoing description is sufficient for purposesof the present application to show the general operation of anelectrophotographic printing machine embodying the teachings of thepresent invention. 1 v

Referring now to the specific subject matter of the present inventionillustrated more clearly in FIGS. 2 and 3, container 38 storing a stackof support material therein will be discussed hereinafter, in detail.Turning tion member, indicated generally at 72 includes a pair ofopposed side members 74 and a rear member 76.

Each side member 74 is affixed to one of the side edge portions of baseplate 62 by suitable means, e.g. adhesive. In this way, side members 74definea pair of op posed spacedgenerally planar surfaces extendingsubstantially in a direction normal to base plate 62. Stack 64 isdisposed onbase plate 62 such that at least one of the side edgeportions thereof engage side members 74. This aligns the'side edges ofeach sheet of support material 34 in registration with one another.Similarly, rear member 76 is attached to base plate 62 by suitablemeans, e.g., an adhesive, defining a generally planar surface extendingsubstantially in a direction normal to side members 74 and base plate62. Rear member 76 is adapted to engage the trailing edge of stack 64 soas to align each sheet of support material 34 in registration with oneanother. Thus, it is evident that the combination of side member 74 andrear member 76, cooperating with one another, insures that both the sideedges and leading and trailing edges of stack 64 are aligned such thateach sheet of support material 34 is in registration with one another. Atop plate 78 is attached to the upper edge portions of side members 74and rear member 76. Top plate 78 in conjunction with base plate 62defines a cavity for storing stack 64. As depicted in FIG. 2, top plate78 has a notch 80 in the region of the leading marginal edge portionthereof affording access to the uppermost sheet of stack 64. Thisenables successive uppermost sheets 34 to be withdrawn from the cavitydefined by top plate 78 and base plate 62. Flexible sheet 66 is,preferably, made from a fibrous material which may be conductive toground static charge thereon. One suitable flexible sheet material isplain paper amongstothers. Flexible sheets 66 is adapted to cooperatewith non-fibrous support material 34 to provide sequential feeding ofsingle sheets preventing machine jams and insuring proper operation oftheelectrophotographic printing machine depicted in FIG. 1.

While the invention has been described in connecthe side and rearmembers attached thereto, one skilled in the art will appreciate thatthe invention is not necessarily so limited and that the container maybe made from sheet metal or plastic in which the base plate side membersand rear member are formed from a single sheet wherein the side and rearmember are bent in an upwardly direction from the base plate.

Referring now to FIG. 3, container 38 is depicted therein in cooperationwith feed roll 40 and retard roll 42. Notched portion 80 of top plate 78enables feed roll 40 to have access to the upper surface of theuppermost sheet 34 of stack 64 disposed on base plate 62. Feed roll 40is adapted to rotate in the direction of arrow 82. Flexible sheet 66 isbent into an arcuate configuration and interposed between retard roll 42and feed roll 40. As feed roll 40 rotates in the direction of arrow 82,it advances the uppermost sheet into the nip between retard roll 42 andfeed roll 40 over flexible sheet 66. The utilizationof fibrous flexiblesheet 66 prevents multiple sheet feeding and permits only a single sheetto pass over flexible sheet 66 between feed roll 40 and retard roll 42.

From the foregoing, it is apparent that the container of the presentinvention cooperates with the feeding most sheets from a stack of sheetmaterial disposed in the container. In particular, the container isadapted to feed successive non-fibrous sheets. Hence, the apparatus ofthe present invention facilitates the automatic sheet feeding ofsuccessive non-fibrous sheets of support material adapted to be utilizedin an electrophotographic printing machine for the formationof coloredtransparencies.

It is, therefore, evident that there as been provided in accordance withthe present invention, a container cooperating with a sheet feedingmechanism for preventing multiple feeding of sheets from a stack thatfully satisfies the objects, aims and advantages set forth above. Whilethis invention has been described in conjunction with a specificembodiment thereof, it is evident that many alternatives, modificationsand variations will be apparent to those skilled in the art.Accordingly, it is intended to embrace all alternatives, modificationsandfvariations that fall within the spirit and broad scope of theappended claims.

What is claimed is:

1. An apparatus for separating and feeding successive single sheets froma stack of sheet material, including:

a rotary driven feed roll, said feed roll being adapted to engage theupper surface of successive uppermostsheets in the stack of sheetmaterial;

a retard roll cooperating with said feed roll for seriatim feeding ofsuccessive uppermost sheets from the stack;

a base plate defining a generally planar surface for supporting thestack; and e a flexible sheet having one marginal edge portion thereofsecured to the leading edge portion of said base plate, said flexiblesheet extending in a substantially outwardly direction beyond said baseplate and being interposed between said feed roll and said retard rollsuch that a portion of the upper surface thereof engages theundersurface of successive uppermost sheets advancing from the stackdisposed on said base plate.

2. An apparatus as recited in claim 1, further including a registrationmember extending substantially in an upwardly direction from base plate,said registration member having a first portion defining a generallyplanar surface engaging one side edge portion of the stack and a secondportion defining a generally planar surface extending substantially in adirection normal to the first portion thereof engaging the trailing edgeportion of the stack to substantially align the sheets thereof inregistration with one another.

3. An apparatus as recited in claim 2, wherein:

the first portion of said registration member includes a side memberdefining a generally planar surface extending substantially in adirection normal to said base plate and being affixed thereto in theregion of one side marginal edge portion thereof; and

the second portion of said registration member includes a rear memberdefining a generally planar surface extending substantially in adirection normal to said side member and said base plate, said rearmember being attached to said base plate in the region in the trailingmarginal edge portion thereof.

4. An apparatus as recited in claim 2, further including a top plateattached to said registration member and having a generally planarsurface extending substantially in a direction parallel to said baseplate defining a cavity therebetween for storing the stack therein, saidtop plate having a notch in the region of the leading marginal portionthereof affording said feed roll access to the upper surface of theuppermost sheet of the stack permitting the advancement thereof from thecavity. i

5. An apparatus forseparating and feeding nonfibrous sheets, as recitedin claim 1, wherein said flexible

1. An apparatus for separating and feeding successive single sheets froma stack of sheet material, including: a rotary driven feed roll, saidfeed roll being adapted to engage the upper surface of successiveuppermost sheets in the stack of sheet material; a retard rollcooperating with said feed roll for seriatim feeding of successiveuppermost sheets from the stack; a base plate defining a generallyplanar surface for supporting the stack; and a flexible sheet having onemarginal edge portion thereof secured to the leading edge portion ofsaid base plate, said flexible sheet extending in a substantiallyoutwardly direction beyond said base plate and being interposed betweensaid feed roll and said retard roll such that a portion of the uppersurface thereof engages the undersurface of successive uppermost sheetsadvancing from the stack disposed on said base plate.
 2. An apparatus asrecited in claim 1, further including a registration member extendingsubstantially in an upwardly direction from base plate, saidregistration member having a first portion defining a generally planarsurface engaging one side edge portion of the stack and a second portiondefining a generally planar surface extending substantially in adirection normal to the first portion thereof engaging the trailing edgeportion of the stack to substantially align the sheets thereof inregistration with one another.
 3. An apparatus as recited in claim 2,wherein: the first portion of said registration member includes a sidemember defining a generally planar surface extending substantially in adirection normal to said base plate and being affixed thereto in theregion of one side marginal edge portion thereof; and the second portionof said registration member includes a rear member defining a generallyplanar surface extending substantially in a direction normal to saidside member and said base plate, said rear member being attached to saidbase plate in the region in the trailing marginal edge portion thereof.4. An apparatus as recited in claim 2, further including a top plateattached to said registration member and having a generally planarsurface extending substantially in a direction parallel to said baseplate defining a cavity therebetween for storing the stack therein, saidtop plate having a notch in the region of the leading marginal portionthereof affording said feed roll access to the upper surface of theuppermost sheet of the stack permitting the advancement thereof from thecavity.
 5. An apparatus for separating and feeding nonfibrous sheets, asrecited in claim 1, wherein said flexible sheet is made from a fibrousmaterial.